Cisco Cisco Unified MeetingPlace Audio Server Manuel De Maintenance
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Cisco MeetingPlace Audio Server 5.2 Customer Engineering Guide (for Cisco MeetingPlace 8112)
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Chapter 4 Configuring the 8112 Server
Configuring the system
About ToS byte
Within the voice packets, the Type of Service (ToS) byte is an 8-bit field in the IP header. It is used for
either IP Precedence or DSCP. (Another term for byte is octet.) When this byte is used for IP Precedence,
three bits are used for the IP Precedence value and four bits are used for the ToS value.
either IP Precedence or DSCP. (Another term for byte is octet.) When this byte is used for IP Precedence,
three bits are used for the IP Precedence value and four bits are used for the ToS value.
The following shows the bit layout:
Note
Note the differences in terminology: the ToS byte includes all 8 bits; but the ToS field is only 4 bits within
this byte. The IP Precedence mechanism partitions the ToS byte into an IP Precedence field and a ToS
field.
this byte. The IP Precedence mechanism partitions the ToS byte into an IP Precedence field and a ToS
field.
When this byte is used for DSCP, six bits are used for DSCP. The following is the bit layout:
Notice that the DSCP field overlaps the fields used for IP Precedence. Therefore, if DSCP values are
chosen carefully, then backward compatibility can be achieved if the customer network has a mixture of
devices (some using IP Precedence, others using DSCP).
chosen carefully, then backward compatibility can be achieved if the customer network has a mixture of
devices (some using IP Precedence, others using DSCP).
IP Precedence
If you use the traditional IP Precedence QoS mechanism, you must provide two values to be used for
MeetingPlace IP configuration:
MeetingPlace IP configuration:
•
IP Precedence value — a value from 0-7. The IP Precedence is used to classify and prioritize types
of traffic. Most implementations use an IP Precedence value of 5. Here is a complete list of values:
of traffic. Most implementations use an IP Precedence value of 5. Here is a complete list of values:
0 – routine
1 – priority
2 – immediate
3 – flash
4 – flash override
5 – CRITIC/ECP
6 – internetwork control
7 – network control
1 – priority
2 – immediate
3 – flash
4 – flash override
5 – CRITIC/ECP
6 – internetwork control
7 – network control
•
ToS value — a value from 0-15. The ToS value can determine special handling of packets, such as
minimizing delay or maximizing throughput. Unless the customer specifies otherwise, this value is
best set to 0.
minimizing delay or maximizing throughput. Unless the customer specifies otherwise, this value is
best set to 0.
The following shows an example of how to use the “blade” command to configure an IP Precedence
value of 5 and a ToS value of 0. Notice that DSCP is disabled.
value of 5 and a ToS value of 0. Notice that DSCP is disabled.
7
6
5
4
3
2
1
0
IP precedence
Type of Service
7
6
5
4
3
2
1
0
Differentiated Services Code Point